Department of Biology, University of York, UK.
BMC Cancer. 2010 Sep 10;10:482. doi: 10.1186/1471-2407-10-482.
Ciz1 promotes initiation of mammalian DNA replication and is present within nuclear matrix associated DNA replication factories. Depletion of Ciz1 from normal and cancer cells restrains entry to S phase and inhibits cell proliferation. Several alternative splicing events with putative functional consequences have been identified and reported, but many more variants are predicted to exist based on publicly available mRNAs and expressed sequence tags.
Here we report the development and validation of a custom exon and exon-junction microarray focused on the human CIZ1 gene, capable of reproducible detection of differential splice-variant expression.
Using a pair of paediatric cancer cell lines and a pool of eight normal lines as reference, the array identified expected and novel CIZ1 splicing events. One novel variant (delta 8-12) that encodes a predicted protein lacking key functional sites, was validated by quantitative RT-PCR and found to be over-represented in a range of other cancer cell lines, and over half of a panel of primary lung tumours.
Expression of CIZ1 delta 8-12 appears to be restricted to cancer cells, and may therefore be a useful novel biomarker.
Ciz1 促进哺乳动物 DNA 复制的起始，存在于核基质相关的 DNA 复制工厂中。从正常和癌细胞中耗尽 Ciz1 会抑制进入 S 期并抑制细胞增殖。已经鉴定并报道了几种具有潜在功能影响的替代剪接事件，但根据公开的 mRNA 和表达序列标签，预计存在更多的变体。
在这里，我们报告了一种针对人类 CIZ1 基因的定制外显子和外显子-连接微阵列的开发和验证，该阵列能够重现性地检测差异剪接变体的表达。
使用一对儿科癌细胞系和一组 8 个正常系作为参考，该阵列鉴定出了预期和新的 CIZ1 剪接事件。一种新的变体（delta 8-12）编码一种缺少关键功能位点的预测蛋白，通过定量 RT-PCR 进行了验证，并在一系列其他癌细胞系中发现存在，并且在一组原发性肺癌肿瘤中超过一半。
CIZ1 delta 8-12 的表达似乎仅限于癌细胞，因此可能是一种有用的新型生物标志物。
